Organic compound, and organic light emitting diode and organic light emitting display device including the same

ABSTRACT

Embodiments of the present invention provide an organic light emitting diode and an organic light emitting display device including the organic compound. The organic compound is capable of reducing a driving voltage of an organic light emitting diode and improves a current efficiency and a lifetime of the organic light emitting diode and the organic light emitting display device including the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. Pat. ApplicationNo. 17/101,701 filed on Nov. 23, 2020, which is a ContinuationApplication of U.S. Pat. Application No. 15/639,622, filed on Jun. 30,2017 (issued as U.S. Pat. No. 10,879,472 on Dec. 29, 2020), which claimspriority under 35 U.S.C. § 119(a) to Korean Patent Application No.10-2016-0082776, filed in Republic of Korea on Jun. 30, 2016, all ofthese applications are hereby expressly incorporated by reference intothe present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an organic compound and moreparticularly to an organic compound being capable of reducing a drivingvoltage of an organic light emitting diode and improving a currentefficiency and a lifetime of the organic light emitting diode and theorganic light emitting display device including the organic compound.

Discussion of the Related Art

As requests for a flat panel display device having a small occupied areahave increased, an organic light emitting display (OLED) deviceincluding an organic light emitting diode has been the subject of recentresearch.

The organic light emitting diode emits light by injecting electrons froma cathode as an electron injection electrode and holes from an anode asa hole injection electrode into an emission compound layer, combiningthe electrons with the holes, generating an exciton, and transformingthe exciton from an excited state to a ground state. A flexiblesubstrate, for example, a plastic substrate, can be used as a basesubstrate where elements are formed. Since the OLED does not require abacklight assembly, the OLED has low weight and low power consumption.Moreover, the OLED can be operated at a voltage (e.g., 10 V or below)lower than a voltage required to operate other display devices.

On the other hand, a white organic light emitting diode are used for alighting apparatus, a thin light source, a backlight unit of a liquidcrystal display device and a full color display device including a colorfilter.

In the white organic light emitting diode, properties of color purity,color stability, emitting efficiency and lifetime are importantconsiderations. For example, the white organic light emitting diode maybe classified into a single-layered emission structure and amulti-layered emission structure. To obtain a long lifetime whiteorganic light emitting diode, the white organic light emitting diodehaving a stack structure of a fluorescent blue emitting layer and aphosphorescent yellow emitting layer may be used. This structure may bereferred to as a tandem structure.

For example, the tandem structure white organic light emitting diode mayinclude a first emitting part including a fluorescent blue emittinglayer and a second emitting part including a phosphorescent yellow-greenemitting layer. The first and second emitting parts may be verticallystacked. In the above tandem structure white organic light emittingdiode, the light from the fluorescent blue emitting layer and the lightfrom the phosphorescent yellow-green emitting layer are mixed to providethe white light.

To increase the current efficiency and improve the charge distribution,the tandem structure white organic light emitting diode further includesa charge generation layer between the first and second emitting parts.The charge generation layer (CGL) may have a P-N junction structure ofan N-type CGL and a P-type CGL.

However, in the related CGL, the charge is generated at an interfacebetween the P-type CGL and a hole injection layer (HIL) or between theP-type CGL and a hole transporting layer (HTL) because of an energydifference between the N-type CGL and the P-type CGL. As a result, anelectron injection property into the N-type CGL is decreased.

In addition, when an alkali metal is doped into the N-type CGL, thealkali metal may be diffused into the P-type CGL such that the lifetimeof the OLED is reduced.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an organic compoundand an organic light emitting diode and an organic light emittingdisplay (OLED) device including the same that substantially obviate oneor more of the problems due to limitations and disadvantages of therelated art.

An object of the present invention is to provide an organic compoundbeing capable of preventing the decrease of an electron injectionproperty and the lifetime.

An object of the present invention is to provide an organic lightemitting diode and an OLED device having improved electron injectionproperty and lifetime.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, anorganic compound is represented by following Formula:

wherein each of X₁ to X₅ is independently selected from a carbon atom(C) or a nitrogen atom (N), and at least two or three of X₁ to X₅ are N,wherein each of R₁ and R₂ is independently selected from a substitutedor non-substituted aryl group or a substituted or non-substitutedheteroaryl group, and “a” is an integer between zero (0) to 3, andwherein each of L₁ and L₂ is independently selected from a substitutedor non-substituted arylene group or a substituted or non-substitutedheteroarylene group, and “b” is zero (0) or 1.

In another aspect, an organic light emitting diode comprises first andsecond electrodes facing each other; a first emitting part between thefirst and second electrodes and including a first emitting materiallayer and an electron transporting layer; a second emitting part betweenthe first emitting part and the second electrode and including a secondemitting material layer; and a charge generation layer between the firstand second emitting parts, wherein at least one of the electrontransporting layer and the charge generation layer includes an organiccompound represented by following Formula:

wherein each of X₁ to X₅ is independently selected from a carbon atom(C) or a nitrogen atom (N), and at least two or three of X₁ to X₅ are N,wherein each of R₁ and R₂ is independently selected from a substitutedor non-substituted aryl group or a substituted or non-substitutedheteroaryl group, and “a” is an integer between zero (0) to 3, andwherein each of L₁ and L₂ is independently selected from a substitutedor non-substituted arylene group or a substituted or non-substitutedheteroarylene group, and “b” is zero (0) or 1.

In another aspect, an organic light emitting display device comprises asubstrate; an organic light emitting diode over the substrate andincluding first and second electrodes facing each other, a firstemitting part between the first and second electrodes and including afirst emitting material layer and an electron transporting layer, asecond emitting part between the first emitting part and the secondelectrode and including a second emitting material layer and a chargegeneration layer between the first and second emitting parts; and a thinfilm transistor between the substrate and the organic light emittingdiode and connected to the first electrode, wherein at least one of theelectron transporting layer and the charge generation layer includes anorganic compound represented by following Formula:

wherein each of X₁ to X₅ is independently selected from a carbon atom(C) or a nitrogen atom (N), and at least two or three of X₁ to X₅ are N,wherein each of R₁ and R₂ is independently selected from a substitutedor non-substituted aryl group or a substituted or non-substitutedheteroaryl group, and “a” is an integer between zero (0) to 3, andwherein each of L₁ and L₂ is independently selected from a substitutedor non-substituted arylene group or a substituted or non-substitutedheteroarylene group, and “b” is zero (0) or 1.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. The patent or application file contains at least one colordrawing. Copies of this patent or patent application publication withcolor drawing will be provided by the USPTO upon request and payment ofthe necessary fee.

FIG. 1 is a schematic cross-sectional view of an OLED device accordingto an embodiment of the present invention.

FIGS. 2A and 2B are schematic cross-sectional views of an organic lightemitting diode according to an embodiment of the present invention,respectively.

FIGS. 3A to 3C are graphs showing emitting properties of an organiclight emitting diode including an organic compound in an electrontransporting layer.

FIGS. 4A to 4C are graphs showing emitting properties of an organiclight emitting diode including an organic compound in an N-type CGL.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of an OLED device accordingto an embodiment of the present invention. All components of the OLEDdevice according to all embodiments of the present invention areoperatively coupled and configured.

As shown in FIG. 1 , an OLED device 100 includes a substrate 110, anorganic light emitting diode D over the substrate 110, an encapsulationfilm 120 covering the organic light emitting diode D.

A driving thin film transistor (TFT) Td is disposed on the substrate110, and the organic light emitting diode D is connected to the drivingTFT Td.

A gate line and a data line are disposed on or over the substrate 110and cross each other to define a pixel region. In addition, a powerline, which is parallel to and spaced apart from the gate line or thedata line, a switching TFT, which is electrically connected to the gateline and the data line, and a storage capacitor, which is connected tothe power line and an electrode of the switching TFT may be formed on orover the substrate 110.

The driving TFT Td is connected to the switching TFT and includes asemiconductor layer 152, a gate electrode 160, a source electrode 170and a drain electrode 172.

The semiconductor layer 152 is formed on the substrate 110. Thesemiconductor layer 152 may be formed of an oxide semiconductor materialor a poly-silicon.

When the semiconductor layer 152 includes the oxide semiconductormaterial, a light-shielding pattern may be formed under thesemiconductor layer 152. The light to the semiconductor layer 152 isshielded or blocked by the light-shielding pattern such that thermaldegradation of the semiconductor layer 152 can be prevented. On theother hand, when the semiconductor layer 152 includes polycrystallinesilicon, impurities may be doped into both sides of the semiconductorlayer 152.

A gate insulating layer 154 is formed on the semiconductor layer 152.The gate insulating layer 154 may be formed of an inorganic insulatingmaterial such as silicon oxide or silicon nitride.

The gate electrode 160, which is formed of a conductive material, e.g.,metal, is formed on the gate insulating layer 154 to correspond to acenter of the semiconductor layer 152. The gate electrode 160 isconnected to the switching TFT.

An interlayer insulating layer 162, which is formed of an insulatingmaterial, is formed on an entire surface of the substrate 110 includingthe gate electrode 160. The interlayer insulating layer 162 may beformed of an inorganic insulating material, e.g., silicon oxide orsilicon nitride, or an organic insulating material, e.g.,benzocyclobutene or photo-acryl.

The interlayer insulating layer 162 includes first and second contactholes 164 and 166 exposing both sides of the semiconductor layer 152.The first and second contact holes 164 and 166 are positioned at bothsides of the gate electrode 160 to be spaced apart from the gateelectrode 160.

The source electrode 170 and the drain electrode 172, which are formedof a conductive material, e.g., metal, are formed on the interlayerinsulating layer 162. The source electrode 170 and the drain electrode172 are spaced apart from each other with respect to the gate electrode160 and respectively contact both sides of the semiconductor layer 152through the first and second contact holes 164 and 166.

In the driving TFT Td, the gate electrode 160, the source electrode 170and the drain electrode 172 are positioned over the semiconductor layer152. Namely, the driving TFT Td has a coplanar structure.

Alternatively, in the driving TFT Td, the gate electrode may bepositioned under the semiconductor layer, and the source and drainelectrodes may be positioned over the semiconductor layer such that thedriving TFT Td may have an inverted staggered structure. In thisinstance, the semiconductor layer may include amorphous silicon.

The switching TFT may have substantially the same structure as thedriving TFT Td.

A passivation layer 174, which includes a drain contact hole 176exposing the drain electrode 172 of the driving TFT Td, is formed tocover the driving TFT Td.

A first electrode 180, which is connected to the drain electrode 172 ofthe driving TFT Td through the drain contact hole 176, is separatelyformed on the passivation layer 174 in each pixel region.

The first electrode 180 may be an anode and may be formed of aconductive material having a relatively high work function. For example,the first electrode 180 may be formed of a transparent conductivematerial, such as indium-tin-oxide (ITO), indium-zinc-oxide (IZO) orzinc oxide (ZnO).

When the OLED device 100 of the present invention is a top-emissiontype, a reflection electrode or a reflection layer may be formed underthe first electrode 180. For example, the reflection electrode or thereflection layer may be formed of aluminum (Al), silver (Ag), nickel(Ni) or aluminum-palladium-copper (APC) alloy.

A bank layer 186, which covers edges of the first electrode 180, isformed on the passivation layer 174. The bank 186 exposes a center ofthe first electrode 180 in the pixel region.

An organic emitting layer 182 is formed on the first electrode 180. Asexplained below, the organic emitting layer includes at least twoemitting parts such that the organic light emitting diode D has a tandemstructure. The emitting parts are vertically stacked.

A second electrode 184 is formed over the substrate 110 including theemitting layer 182. The second electrode 184 is positioned at an entiresurface of the display area. The second electrode 184 may be a cathodeand may be formed of a conductive material having a relatively low workfunction. For example, the second electrode 184 may be formed ofaluminum (Al), magnesium (Mg) or Al-Mg alloy.

The first electrode 180, the emitting layer 182 and the second electrode184 constitute the organic light emitting diode D.

The encapsulation film 120 is formed on the organic light emitting diodeD to prevent penetration of moisture into the organic light emittingdiode D. For example, the encapsulation film 120 may has atriple-layered structure of a first inorganic layer, an organic layerand a second inorganic layer. However, it is not limited thereto.

FIGS. 2A and 2B are schematic cross-sectional views of an organic lightemitting diode according to an embodiment of the present invention,respectively.

As shown in FIG. 2A, the organic light emitting diode D includes a firstelectrode 180, a second electrode 184, an organic emitting layer 182between the first and second electrodes 180 and 184 and including firstand second emitting parts ST1 and ST2 and a charge generation layer(CGL) 230.

As mentioned above, the first electrode 180 is the anode for injecting ahole and includes a high work function conductive material, e.g., ITO,IZO or ZO. The second electrode 184 is the cathode for injecting anelectron and includes a low work function conductive material, e.g., Al,Mg or Al-Mg alloy.

The CGL 230 is positioned between the first and second emitting partsST1 and ST2. Namely, the first emitting part ST1, the CGL 230 and thesecond emitting part ST2 are sequentially stacked on the first electrode180. In other words, the first emitting part ST1 is positioned betweenthe first electrode 180 and the CGL 230, and the second emitting partST2 is positioned between the second electrode 184 and the CGL 230.

The first emitting part ST1 may include a hole injection layer (HIL)212, a first hole transporting layer (HTL) 214, a first emittingmaterial layer (EML) 216 and a first electron transporting layer (ETL)218 sequentially stacked on the first electrode 180. Namely, the HIL 212and the first HTL 214 are positioned between the first electrode 180 andthe first EML 216, and the HIL 212 is positioned between the firstelectrode 180 and the first HTL 214. In addition, the first ETL 218 ispositioned between the first EML 216 and the CGL 230.

A hole injection from the first electrode 180 into the first EML 216 isimproved by the HIL 212. The HIL 212 may include at least one selectedfrom the group consisting of copper phthalocyanine (CuPC),poly(3,4)-ethylenedioxythiophene (PEDOT) and polyaniline, but it is notlimited thereto.

The HIL 212 may have a thickness of about 1 to 150 nm. The holeinjection property may be improved with a thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of athickness of the HIL 212 may be prevented with a thickness below 150 nm.The HIL 212 may be omitted according to the structure or property of theorganic light emitting diode.

A hole transporting is improved by the first HTL 214. The first HTL 214may include at least one selected from the group consisting ofN,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (NPD),N,N′-bis-(3-methylphenyl)-N,N′-bis-(phenyl)-benzidine (TPD),2,2′,7,7′-tetrakis(N,N-diphenylamino)-9,9′-spirofluorene (spiro-TAD) and4,4′,4″-Tris(N-3-methylphenyl-N-phenylamino)-triphenylamine (MTDATA),but it is not limited thereto.

The first HTL 214 may have a thickness of about 1 to 150 nm. The holetransporting property may be improved with a thickness above 1 nm, andan increase of the driving voltage resulting from an increase of athickness of the first HTL 214 may be prevented with a thickness below150 nm.

The first EML 216 may be a blue EML. Alternatively, the first EML 216may be a red EML, a green EML or a yellow EML. When the first EML 216 isthe blue EML, the first EML 216 may be a dark blue EML or a sky blueEML. In addition, the first EML 216 may be a double-layered structure ofthe blue EML and the red EML, the blue EML and yellow-green EML, or theblue EML and the green EML.

When the first EML 216 is the red EML, the first EML 216 may be aphosphorescent EML including a host, e.g.,4,4′-bis(carbazol-9-yl)biphenyl (CBP), and at least one dopant selectedfrom the group consisting of bis(1-phenylisoquinoline)acetylacetonateiridium (PIQIr(acac), bis(1-phenylquinoline)acetylacetonateiridium(PQIr(acac), tris(1-phenylquinoline)iridium(PQIr) andoctaethylporphyrin platinum (PtOEP), but it is not limited thereto.Alternatively, the first EML 216 may be a fluorescent EML includingPBD:Eu(DBM)3(Phen) or perylene. In this instance, the first emittingpart ST1 has an emission peak range of about 600 to 650 nm.

When the first EML 216 is the green EML, the first EML 216 may be aphosphorescent EML including a host, e.g., CBP, and a dopant of iridiumcomplex, but it is not limited thereto. Alternatively, the first EML 216may a fluorescent EML including tris(8-hydroxyquinolinato)aluminum(Alq3). In this instance, the first emitting part ST1 has an emissionpeak range of about 510 to 570 nm.

When the first EML 216 is the blue EML, the first EML 216 may be aphosphorescent EML including a host, e.g., CBP, and a dopant of iridiumcomplex, but it is not limited thereto. Alternatively, the first EML 216may a fluorescent EML including spiro-DPVBi, Spiro-CBP, distyryl benzene(DSB), distyryl arene (DSA), PFO-based polymer or PPV-based polymer. Asmentioned above, the first EML 216 may be a sky blue EML or deep blue(dark blue) EML. In this instance, the first emitting part ST1 has anemission peak range of about 440 to 480 nm.

On the other hand, to improve the emitting efficiency (red efficiency),the first emitting part ST1 may include two EMLs. For example, the firstemitting part ST1 may include the blue EML and the red EML. In thisinstance, the first emitting part ST1 has an emission peak range ofabout 440 to 650 nm.

In addition, the first EML 216 may have a single-layered structure ofthe yellow-green EML or a double-layered structure of the yellow-greenEML and the green EML. In this instance, the first EML 216 may includeat least one host selected from the group consisting of CBP andbis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium (BAlq) and aphosphorescent yellow-green dopant. The first emitting part ST1 has anemission peak range of about 510 to 590 nm.

When the first emitting part ST1 includes two EMLs of the yellow-greenEML and the red EML to improve the emitting efficiency (red efficiency),the first emitting part ST1 has an emission peak range of about 510 to650 nm.

An electron transporting is improved by the first ETL 218. The first ETL218 may include an organic compound represented by Formula 1,tris(8-hydroxy-quinolinato)aluminum (Alq3),2-(4-biphenyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD),3-(4-biphenyl)-4-phenyl-5-tertbutylphenyl-1,2,4-triazole (TAZ) orBis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum (BAlq), but itis not limited thereto.

The first ETL 218 may have a thickness of about 1 to 150 nm. Theelectron transporting property may be improved with a thickness above 1nm, and an increase of the driving voltage resulting from an increase ofa thickness of the first ETL 218 may be prevented with a thickness below150 nm.

The second emitting part ST2 may include a second HTL 222, a second EML224, a second ETL 226 and an electron injection layer (EIL) 228. Thesecond HTL 222 is positioned between the CGL 230 and the second EML 224,and the second ETL 226 is positioned between the second EML 224 and thesecond electrode 184. In addition, the EIL 228 is positioned between thesecond ETL 226 and the second electrode 184.

The second HTL 222 and the second ETL 226 may be the same as ordifferent from the first HTL 214 and the first ETL 218 in the firstemitting part ST1, respectively. The ElL 228 may be omitted according tothe structure or property of the organic light emitting diode.

The second EML 224 may be red, green, blue or yellow-green EML. Forexample, when the first EML 216 is the blue EML, the second EML 224 maybe yellow-green EML. Alternatively, the first EML 216 may be theyellow-green EML, and the second EML 224 may be the blue EML.

When the second EML 224 is the yellow-green EML, the second EML 224 mayhave a single-layered structure of the yellow-green EML or adouble-layered structure of the yellow-green EML and the green EML. Forexample, the single-layered second EML 224 may include at least one hostselected from the group consisting of CBP andbis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium (BAlq) and aphosphorescent yellow-green dopant, but it is not limited thereto.

An electron injection is improved by the EIL 228. The EIL 228 mayinclude at least one selected from the group consisting oftris(8-hydroxy-quinolinato)aluminum (Alq3),2-(4-biphenyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD),3-(4-biphenyl)-4-phenyl-5-tertbutylphenyl-1,2,4-triazole TAZ) andBis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum (BAlq), but itis not limited thereto.

On the other hand, the EIL 228 may further include a metal compound. Forexample, the metal compound may be at least one selected from the groupconsisting of LiF, NaF, KF, RbF, CsF, FrF, BeF2, MgF2, CaF2, SrF2, BaF2and RaF2, but it is not limited thereto.

The EIL 228 may have a thickness of about 1 to 50 nm. The electroninjection property may be improved with a thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of athickness of the EIL 228 may be prevented with a thickness below 50 nm.

The CGL 230 is positioned between the first emitting part ST1 and thesecond emitting part ST2. Namely, the first and second emitting partsST1 and ST2 are connected by the CGL 230. The CGL 230 may be a P-Njunction type CGL including an N-type CGL 230N and a P-type CGL 230P.

The N-type CGL 230N is positioned between the first ETL 218 and thesecond HTL 222, and the P-type CGL 230P is positioned between the N-typeCGL 230N and the second HTL 222.

The CGL 230 generates a charge or separates a charge into a hole and anelectron such that the hole and the electron are provided into the firstand second emitting parts ST1 and ST2.

The N-type CGL 230N provides the electron into the first ETL 218 of thefirst emitting part ST1, and the first ETL 218 provide the electron intothe first EML 216 of the first emitting part ST1. On the other hand, theP-type CGL 230P provide the hole into the second HTL 222 of the secondemitting part ST2, and the second HTL 222 provide the hole into thesecond EML 224 of the second emitting part ST2. Accordingly, theemitting efficiency of the organic light emitting diode D including aplurality of EMLs or a plurality of emitting parts is improved, and thedriving voltage of the organic light emitting diode D is reduced.

Referring to FIG. 2B, an organic light emitting diode D includes a firstelectrode 180, a second electrode 184, an organic emitting layer 182between the first and second electrodes 180 and 184 and including firstto third emitting parts ST1, ST2 and ST3 and first and second chargegeneration layers (CGLs) 230 and 250. Alternatively, four or moreemitting parts and three or more CGLs may be disposed between the firstand second electrodes 180 and 184.

As mentioned above, the first electrode 180 is the anode for injecting ahole and includes a high work function conductive material, e.g., ITO,IZO or ZO. The second electrode 184 is the cathode for injecting anelectron and includes a low work function conductive material, e.g., Al,Mg or Al-Mg alloy.

The first and second CGLs 230 and 250 are positioned between the firstand second emitting parts ST1 and ST2 and the second and third emittingparts ST2 and ST3, respectively. Namely, the first emitting part ST1,the first CGL 230, the second emitting part ST2, the second CGL 250 andthe third emitting part ST3 are sequentially stacked on the firstelectrode 180. In other words, the first emitting part ST1 is positionedbetween the first electrode 180 and the first CGL 230, and the secondemitting part ST2 is positioned between the First and Second CGLs 230and 250. In addition, the third emitting part ST3 is positioned betweenthe second electrode 184 and the second CGL 250.

The first emitting part ST1 may include an HIL 212, a first HTL 214, afirst EML 216 and a first ETL 218 sequentially stacked on the firstelectrode 180. Namely, the HIL 212 and the first HTL 214 are positionedbetween the first electrode 180 and the first EML 216, and the HIL 212is positioned between the first electrode 180 and the first HTL 214. Inaddition, the first ETL 218 is positioned between the first EML 216 andthe first CGL 230.

The HIL 212, the first HTL 214, the first EML 216 and the first ETL 218may have substantially the same property and structure as those in FIG.2A. For example, the first EML 216 may be a blue EML such that the firstemitting part ST1 may have an emission peak range of about 440 to 480nm.

The second emitting part ST2 may include a second HTL 222, a second EML224 and a second ETL 226. The second HTL 222 is positioned between thefirst CGL 230 and the second EML 224, and the second ETL 226 ispositioned between the second EML 224 and the second CGL 250.

The second HTL 222, second EML 224 and the second ETL 226 may havesubstantially the same property and structure as those in FIG. 2A. Forexample, the second EML 224 may be a yellow-green EML such that thesecond emitting part ST2 may have an emission peak range of about 510 to590 nm.

The third emitting part ST3 may include a third HTL 242, a third EML244, a third ETL 246 and an EIL 248. The third HTL 242 is positionedbetween the second CGL 250 and the third EML 244, and the third ETL 246is positioned between the third EML 244 and the second electrode 184. Inaddition, the EIL 248 is positioned between the third ETL 246 and thesecond electrode 184.

The third HTL 242, the third ETL 246 and the EIL 248 may havesubstantially the same property and structure as the second HTL 222, thesecond ETL 226 and the EIL 228 in FIG. 2A.

The first CGL 230 is positioned between the first emitting part ST1 andthe second emitting part ST2, and the second CGL 250 is positionedbetween the second emitting part ST2 and the third emitting part ST3.Each of the first and second CGLs 230 and 250 may be a P-N junction typeCGL. The first CGL 230 includes an N-type CGL 230N and a P-type CGL230P, and the second CGL 250 includes an N-type CGL 250N and a P-typeCGL 250P.

In the first CGL 230, the N-type CGL 230N is positioned between thefirst ETL 218 and the second HTL 222, and the P-type CGL 230P ispositioned between the N-type CGL 230N and the second HTL 222.

In the second CGL 250, the N-type CGL 250N is positioned between thesecond ETL 226 and the third HTL 242, and the P-type CGL 250P ispositioned between the N-type CGL 250N and the third HTL 242.

Each of the first and second CGLs 230 and 250 generates a charge orseparates a charge into a hole and an electron such that the hole andthe electron are provided into the first to third emitting parts ST1 toST3.

Namely, in the first CGL 230, the N-type CGL 230N provides the electroninto the first ETL 218 of the first emitting part ST1, and the P-typeCGL 230P provide the hole into the second HTL 222 of the second emittingpart ST2.In addition, in the second CGL 250, the N-type CGL 250Nprovides the electron into the second ETL 226 of the second emittingpart ST2, and the P-type CGL 250P provide the hole into the third HTL242 of the third emitting part ST3. Accordingly, the emitting efficiencyof the organic light emitting diode D including a plurality of EMLs or aplurality of emitting parts is improved, and the driving voltage of theorganic light emitting diode D is reduced.

However, when the electrons are transported from the N-type CGLs 230Nand 250N into the first and second ETLs 218 and 226, the driving voltageis increased because of a lowest unoccupied molecular orbital (LUTMO)energy level difference between each of the first and second ETLs 218and 226 and each of the N-type CGLs 230N and 250N.

To overcome the above problem, at least one of the first and second ETLs218 and 226 and the N-type CGLs 230N and 250N includes an organiccompound represented in Formula 1. In addition, each of the N-type CGLs230N and 250N may further include alkali metal or alkali earth metal.

As shown in Formula 1, the organic compound of the present inventionincludes a phenanthroline core. Due to the phenanthroline core, anelectron transporting property of the organic compound is improved. Inaddition, a diffusion problem of the alkali metal or the alkali earthmetal from the N-type CGL into the P-type CGL is prevented.

In Formula 1, each of X₁ to X₅ is independently selected from a carbonatom (C) or a nitrogen atom (N), and at least two or three of X₁ to X₅are N.

In Formula 1, each of R₁ and R₂ is independently selected from asubstituted or non-substituted aryl group or a substituted ornon-substituted heteroaryl group, and “a” is an integer between zero (0)to 3.

Each of R1 and R2 is independently selected from C6 to C60 aryl or C6 toC60 heteroaryl. For example, each of R1 and R2 may be selected from oneof phenyl, alkylphenyl, biphenyl, alkylbiphenyl, halophenyl,alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl, naphthyl,alkylnaphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl,phenylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl,alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl, halopyrimidyl,cyanopyridimyl, alkoxypyrimidyl, phenylpyrimidyl, quinolinyl,isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl,naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl,arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl, imidazolyl,carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, phenylterpyridinyl,triphenylenyl, fluoranthenyl and diazafluorenyl.

As a result, due to a pendant including a nitrogen atom, an electrontransporting property of the organic compound is further improved, and ahighest occupied molecular orbital (HOMO) energy level and the LUMOenergy level of the organic compound are controlled.

In addition, a carrier mobility of the organic compound is controlled bylinkers L1 and L2. In Formula 1, each of L1 and L2 is independentlyselected from a substituted or non-substituted arylene group or asubstituted or non-substituted heteroarylene group, and “b” is zero (0)or 1.

Each of L1 and L2 is independently selected from C6 to C60 arylene or C6to C60 heteroarylene. For example, L1 may be selected from one ofphenylene, alkylphenylene, cyanophenylene, naphthylene,alkylnaphthylene, biphenylene, alkylbiphenylene, anthracenylene,pyrenylene, benzothiophenylene, benzofuranylene, dibenzothiophenylene,arylthiazolylene, dibenzofuranylene, fluorenylene and triphenylenylene,and L2 may be one of phenylene and naphthylene.

Namely, since the organic compound of the present invention includes thephenanthroline core having two nitrogen atoms, which have a richelectron property, a layer including the organic compound has highelectron mobility such that an electron transporting property of thelayer is improved. Accordingly, in the organic light emitting diodeincluding the organic compound in the electron transporting layer, anelectron from the N-type CGL into the EML is efficiently transported.

In addition, when the organic compound of the present invention havingthe nitrogen atom of a relatively electron rich sp2 hybrid orbital isincluded in the N-type CGL, the nitrogen atom of the organic compound iscombined or bound with the alkali metal or the alkali earth metal as adopant in the N-type CGL to form a gap state. As a result, an electrontransporting property from the N-type CGL into the ETL is improved.

Moreover, since the alkali metal or the alkali earth metal is combinedwith the nitrogen atom in the organic compound, the diffusion of thealkali metal or the alkali earth metal into the P-type CGL is prevented.

Furthermore, the N-type CGL and the HTL include the organic compoundsuch that the LUMO energy level difference between the N-type CGL andthe HTL is decreased.

Accordingly, when the organic compound of the present invention is usedfor the N-type CGL and/or the ETL of the organic light emitting diode,the driving voltage of the organic light emitting diode is reduced andthe emitting efficiency and the lifetime of the organic light emittingdiode are improved.

The organic compound of the present invention for at least one of theN-type CGLs 230N and 250N and the ETLs 218, 226 and 246 may be one ofmaterials in Formula 2. [Formula 2]

For example, like the compounds A-2, A-4, A-24, A-40, A-49, A-62, and soon, naphthalene may be combined at a 2-position of the phenanthrolinecore. In this instance, an energy level difference between the N-typeCGL and the ETL is reduced such that a tunneling effect for electrontransporting is improved or maximized. Namely, in the present invention,the organic compound is included in the N-type CGL and/or the ETL suchthat the electron transporting property is improved or maximized by thetunneling effect.

In addition, when the organic compound is included in the N-type CGLand/or the ETL, the LUMO energy level difference between the ETL and theN-type CGL is reduced. As a result, the driving voltage increasingproblem resulting from the electron transporting from the N-type CGLinto the ETL is prevented.

Synthesis 1. Synthesis of Compound A-1 (1) Compound B-1

1-(4-bromophenyl)ethanone (15 g, 0.075 mol),8-aminoquinoline-7-carbaldehyde (13 g, 0.075 mol), absolute ethanol (800ml) and KOH (15 g) were input into the round bottom flask, and atemperature was increased. The mixture was refluxed and stirred forabout 15 minutes. The solution was cooled into the room temperature andextracted by using methylene chloride (MC) and water such that anorganic layer is obtained. The organic layer was concentrated under thereduced pressure and re-crystalized by using ethylene acetate such thatthe compound B-1 (2-(4-bromophenyl)-1,10-phenanthroline, 13.7 g) isobtained.

(2) Compound A-1

The compound B-1 (10 g, 0.03 mol),2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyrimidin(10.1g, 0.04 mol), tetrakis(triphenylphosphine)palladium(0) (1.4 g, 0.1mmol), toluene (200 ml), ethanol (40 ml) and 4 M K2CO3 (Potassiumcarbonate, 15 ml) were refluxed and stirred for about 12 hours in theround bottom flask. After completion of the reaction, the reactingsolution was filtered to obtain a crude product. A column separationprocess using a solvent (CHC13:MeOH(Methanol)=10:1) is performed toobtain the compound A-1 (5.5 g).

2. Synthesis of Compound A-2 (1) Compound B-2

1-(1-bromonaphthalen-4-yl)ethanone (14.5 g, 0.058 mol),8-aminoquinoline-7-carbaldehyde (10 g, 0.058 mol), absolute ethanol (800ml) and KOH(potassium hydroxide, 13 g) were input into the round bottomflask, and a temperature was increased. The mixture was refluxed andstirred for about 15 minutes. The solution was cooled into the roomtemperature and extracted by using methylene chloride (MC) and watersuch that an organic layer is obtained. The organic layer wasconcentrated under the reduced pressure and re-crystalized by usingethylene acetate such that the compound B-2(2-(1-bromonaphthalen-4-yl)-1,10-phenanthroline, 10.5 g) is obtained.

(2) Compound A-2

The compound B-2 (10 g, 0.03 mol),2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyrimidine(8.8g, 0.03 mol), tetrakis(triphenylphosphine)palladium(0) (1.2 g, 0.1mmol), toluene 200 ml, ethanol (40 ml) and 4 M K2CO3 (13 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CHC13:MeOH=10:1) is performed to obtain the compound A-2 (6.2 g).

3. Synthesis of Compound A-4

The compound B-2 (10 g, 0.03 mol),2-(1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-4-yl)pyrimidine(10.3 g, 0.03 mol), tetrakis(triphenylphosphine)palladium(0) (1.2 g, 0.1mmol), toluene 200 ml, ethanol (40 ml) and 4 M K2CO3 (13 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CHC13:MeOH=10:1) is performed to obtain the compound A-4 (6.0 g).

4. Synthesis of Compound A-7 (1) Compound B-3

The compound B-2 (10 g, 0.03 mol), bis(pinacolato)diboron (9.1 g, 0.04mol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (1.3g, 0.2 mmol), KOAc(potassium acetate, 10.5 g, 0.11 mol) and 1,4-dioxane(200 ml) were input into the round bottom flask, and a temperature wasincreased. The mixture was refluxed and stirred for about 12 hours. Thesolution was cooled into the room temperature and filtered by usingcelite. Then, the celite was washed by CHCl3. The remaining solution wasconcentrated under the reduced pressure and re-crystalized by usingethylene acetate such that the compound B-3(2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1,10-phenanthroline,8.3 g) is obtained.

(2) Compound A-7

The compound B-3 (5 g, 0.01 mol),2-(10-bromoanthracen-9-yl)pyrimidine(5.3 g, 0.02 mol),tetrakis(triphenylphosphine)palladium(0) (0.6 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (7 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using CHCl3 to obtainthe compound A-7 (3.8 g).

5. Synthesis of Compound A-10

2-bromo-1,10-phenanthroline(5 g, 0.02 mol),2-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)triphenylen-7-yl)pyrimidine(7.2g, 0.02 mol), tetrakis(triphenylphosphine)palladium(0) (0.7 g, 0.06mmol), toluene (150 ml), ethanol (20 ml) and 4 M K2CO3 (8 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CHCl3:MeOH=10:1) is performed, and the resultant is re-crystallized byusing CHCl3 to obtain the compound A-10 (3.6 g).

6. Synthesis of Compound A-20 (1) Compound B-4

The compound B-2 (10 g, 0.075 mol), bis(pinacolato)diboron (7.9 g, 0.04mol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (1.1g, 0.2 mmol), KOAc (9.2 g, 0.09 mol) and 1,4-dioxane (200 ml) were inputinto the round bottom flask, and a temperature was increased. Themixture was refluxed and stirred for about 12 hours. The solution wascooled into the room temperature and filtered by using celite. Then, thecelite was washed by CHCl3. The remaining solution was concentratedunder the reduced pressure and re-crystalized by using ethylene acetatesuch that the compound B-4(2-(1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-4-yl)-1,10-phenanthroline,7.9 g) is obtained.

(2) Compound A-20

The compound B-4 (5 g, 0.01 mol),2-(4-bromophenyl)-4,6-diphenylpyrimidine(5.4 g, 0.01 mol),tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (6 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using CHCl3 to obtainthe compound A-20 (3.9 g).

7. Synthesis of Compound A-24

The compound B-4 (5 g, 0.01 mol),2-bromo-4,6-(bisbiphenyl-4-yl)pyrimidine (5.9 g, 0.01 mol),tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (6 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHC13:MeOH=10:1) isperformed, and the resultant is re-crystallized by using CHCl3 to obtainthe compound A-24 (4.0 g).

8. Synthesis of Compound A-35

The compound B-4 (5 g, 0.01 mol),5-(10-bromoanthracen-9-yl)-2-phenylpyrimidine(5.7 g, 0.01 mol),tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.05 mmol), toluene 150ml, ethanol (20 ml) and 4 M K2CO3 (6 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using CHCl3 to obtainthe compound A-35 (3.8 g).

9. Synthesis of Compound A-40

The compound B-4 (5 g, 0.01 mol), 2-(10-bromoanthracen-9-yl)pyrazine(4.7g, 0.01 mol), tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.04mmol), toluene 150 ml, ethanol (20 ml) and 4 M K2CO3 (6 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CFCl3:MeOH=10:1) is performed, and the resultant is re-crystallized byusing CHCl3 to obtain the compound A-40 (3.2 g).

10. Synthesis of Compound A-42

The compound B-3 (5 g, 0.01 mol),2-(1-bromonaphthalen-4-yl)-5-phenylpyrazine (5.7 g, 0.02 mol),tetrakis(triphenylphosphine)palladium(0) (0.6 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (7 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-42 (3.8 g).

11. Synthesis of Compound A-48

The compound B-3 (5 g, 0.01 mol),4-(4-bromophenyl)-2,6-diphenylpyrimidine(6.1 g, 0.02 mol),tetrakis(triphenylphosphine)palladium(0) (0.6 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (7 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-48 (3.9 g).

12. Synthesis of Compound A-49

The compound B-4 (5 g, 0.01 mol),4-(4-bromophenyl)-2,6-diphenylpyrimidine(5.4 g, 0.01 mol),tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (6 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl3:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-49 (3.7 g).

13. Synthesis of Compound A-50

The compound B-3 (5 g, 0.01 mol),4-(1-bromonaphthalen-4-yl)-2,6-diphenylpyrimidine(6.9 g, 0.02 mol),tetrakis(triphenylphosphine)palladium(0) (0.6 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K2CO3 (7 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. Aftercompletion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHC13:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-50 (4.2 g).

14. Synthesis of Compound A-51

The compound B-3 (5 g, 0.01 mol),4-bromo-2-phenyl-6-(biphenyl-4-yl)pyrimidine(6.1 g, 0.02 mol),tetrakis(triphenylphosphine)palladium(0) (0.6 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K₂CO₃ (7 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl₃:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-51 (3.9 g).

15. Synthesis of Compound A-62

The compound B-4 (5 g, 0.01 mol),2-chloro-4,6-diphenyl-1,3,5-triazine(3.7 g, 0.01 mol),tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.05 mmol), toluene 100ml, ethanol (20 ml) and 4 M K₂CO₃ (6 ml) were refluxed and stirred forabout 12 hours in the round bottom flask. After completion of thereaction, the reacting solution was filtered to obtain a crude product.A column separation process using a solvent (CHCl₃:MeOH=10:1) isperformed, and the resultant is re-crystallized by using methylenedichloride to obtain the compound A-62 (2.8 g).

16. Synthesis of Compound A-63

The compound B-1 (5 g, 0.03 mol),2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-4,6-diphenyl-1,3,5-triazine(7.8g, 0.02 mol), tetrakis(triphenylphosphine)palladium(0) (0.7 g, 0.06mmol), toluene 100 ml, ethanol (20 ml) and 4 M K₂CO₃ (7 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CHCl₃:MeOH=10:1) is performed, and the resultant is re-crystallized byusing methylene dichloride to obtain the compound A-63 (3.8 g).

17. Synthesis of Compound A-67

2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9-phenyl-1,10-phenanthroline (5 g, 0.01 mol), 4-(4-bromophenyl)-2,6-diphenylpyrimidine (5.1 g,0.01 mol), tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.04 mmol),toluene 150 ml, ethanol (20 ml) and 4 M K₂CO₃ (6 ml) were refluxed andstirred for about 12 hours in the round bottom flask. After completionof the reaction, the reacting solution was filtered to obtain a crudeproduct. A column separation process using a solvent (CHCl₃:MeOH=10:1)is performed, and the resultant is re-crystallized by using CHCl₃ toobtain the compound A-67 (4.2 g).

18. Synthesis of Compound A-68

2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9-phenyl-1,10-phenanthroline (5 g, 0.01 mol), 4-(1-bromonaphthalen-4-yl)-2,6-diphenylpyrimidine(5.7 g, 0.01 mol), tetrakis(triphenylphosphine)palladium(0) (0.5 g, 0.04mmol), toluene 150 ml, ethanol (20 ml) and 4 M K₂CO₃ (6 ml) wererefluxed and stirred for about 12 hours in the round bottom flask. Aftercompletion of the reaction, the reacting solution was filtered to obtaina crude product. A column separation process using a solvent(CHCl₃:MeOH=10:1) is performed, and the resultant is re-crystallized byusing CHCl₃ to obtain the compound A-68 (3.8 g).

Organic Light Emitting Diode 1. Comparative Example (Ref)

An ITO layer is deposited and patterned on a substrate and washed toform the anode (2 mm*2 mm). The substrate is loaded in a vacuum chamberhaving a base pressure of 5~7*10~8, and layers are sequentiallydeposited as below.

(1) the HIL (NPD and F4-TCNQ (10 wt% doping), 100 Å), (2) the first HTL(NPD, 1200 Å), (3) the first (blue) EML (anthracene host and pyrenedopant (4 wt% doping), 200 Å), (4) the first ETL (TmPyPB, 100 Å), (5)the N-type CGL (BPhene and Li (2 wt% doping), 100 Å), (6) the P-type CGL(NPD and F4-TCNQ (10 wt% doping), 200 Å),(7) the second HTL (NPD, 200Å),(8) the second (yellow) EML (CBP host and Ir dopant (10 wt% doping),200 Å),(9) the second ETL (Alq3, 100 Å), (10) the EIL (LiF, 5 Å) and(11) the cathode (Al, 2000 Å).

2. Examples (1) Example 1 (compound A-4)

The organic light emitting diode of “Example 1” is provided using thecompound A-4 into the first ETL instead of the material of the first ETLin “Comparative Example”.

(2) Example 2 (compound A-7)

The organic light emitting diode of “Example 2” is provided using thecompound A-7 into the first ETL instead of the material of the first ETLin “Comparative Example”.

(3) Example 3 (compound A-24)

The organic light emitting diode of “Example 3” is provided using thecompound A-24 into the first ETL instead of the material of the firstETL in “Comparative Example”.

(4) Example 4 (compound A-48)

The organic light emitting diode of “Example 4” is provided using thecompound A-48 into the first ETL instead of the material of the firstETL in “Comparative Example”.

(5) Example 5 (compound A-62)

The organic light emitting diode of “Example 5” is provided using thecompound A-62 into the first ETL instead of the material of the firstETL in “Comparative Example”.

The driving voltage, the external quantum efficiency (EQE) and thelifetime of the organic light emitting diodes of “Comparative Example”and “Example 1” to “Example 5” are measured and listed in Table 1. Thecurrent density, the EQE and the lifetime are shown in FIGS. 3A to 3C.

TABLE 1 voltage [%] EQE [%] lifetime [%] Ref 100 100 100 A-4 106 102 102A-7 106 96 156 A-24 104 99 108 A-48 100 102 119 A-62 100 99 144

As shown in Table 1 and FIGS. 3A to 3C, in comparison to “ComparativeExample”, all of the EQE and the lifetime of the organic light emittingdiode using the organic compound of the present invention in the firstETL are improved or at least one of the EQE and the lifetime of theorganic light emitting diode using the organic compound of the presentinvention in the first ETL is remarkably improved.

For example, all of the EQE and the lifetime of the organic lightemitting diode using the compound A-4 in the first ETL are increased. Onthe other hand, in the organic light emitting diode using the compoundA-7 in the first ETL, although the EQE is slightly decreased, thelifetime is remarkably increased.

3. Examples (1) Example 6 (compound A-2)

The organic light emitting diode of “Example 6” is provided using thecompound A-2 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(2) Example 7 (compound A-10)

The organic light emitting diode of “Example 7” is provided using thecompound A-10 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(3) Example 8 (compound A-40)

The organic light emitting diode of “Example 8” is provided using thecompound A-40 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(4) Example 9 (compound A-49)

The organic light emitting diode of “Example 9” is provided using thecompound A-49 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(5) Example 10 (compound A-50)

The organic light emitting diode of “Example 10” is provided using thecompound A-50 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(6) Example 11 (compound A-52)

The organic light emitting diode of “Example 11” is provided using thecompound A-52 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(7) Example 12 (compound A-67)

The organic light emitting diode of “Example 12” is provided using thecompound A-67 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

(8) Example 13 (compound A-68)

The organic light emitting diode of “Example 13” is provided using thecompound A-68 into the N-type CGL instead of the material of the N-typeCGL in “Comparative Example”.

The driving voltage, the external quantum efficiency (EQE) and thelifetime of the organic light emitting diodes of “Comparative Example”and “Example 6” to “Example 13” are measured and listed in Table 2. Thecurrent density, the EQE and the lifetime are shown in FIGS. 4A to 4C.

TABLE 2 voltage [%] EQE [%] lifetime [%] Ref 100 100 100 A-2 105 101 117A-10 106 93 192 A-40 100 97 132 A-49 100 101 143 A-50 98 96 109 A-52 10099 129 A-67 98 100 110 A-68 98 101 156

As shown in Table 2 and FIGS. 4A to 4C, in comparison to “ComparativeExample”, all of the EQE and the lifetime of the organic light emittingdiode using the organic compound of the present invention in the N-CGLare improved or at least one of the EQE and the lifetime of the organiclight emitting diode using the organic compound of the present inventionin the N-CGL is remarkably improved.

For example, all of the EQE and the lifetime of the organic lightemitting diode using the compound A-2 in the N-CGL are increased. On theother hand, in the organic light emitting diode using the compound A-10in the N-CGL, although the EQE is slightly decreased, the lifetime isremarkably increased.

As mentioned above, the organic compound of the present inventionincludes the phenanthroline core having the nitrogen atom of arelatively electron rich sp2 hybrid orbital such that the organiccompound has excellent electron transporting property.

In addition, the nitrogen atom of the organic compound is combined orbound with the alkali metal or the alkali earth metal as a dopant in theN-type CGL to form a gap state such that an electron transportingproperty from the N-type CGL into the ETL is improved.

Moreover, since the alkali metal or the alkali earth metal is combinedwith the nitrogen atom in the organic compound, the diffusion of thealkali metal or the alkali earth metal into the P-type CGL is prevented.

Accordingly, when the organic compound of the present invention is usedfor the N-type CGL and/or the ETL of the organic light emitting diode,the organic light emitting diode and the OLED device have advantages inthe driving voltage, the emitting efficiency and the lifetime.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An organic compound, represented by followingFormula:

wherein each of X₁ and X₄ is a nitrogen atom, and each of X₂, X₃ and X₅is a carbon atom, wherein each of R₁ and R₂ is independently selectedfrom a substituted aryl group, a non-substituted aryl group, asubstituted heteroaryl group or a non-substituted heteroaryl group,wherein a is an integer between 0 to 3, and c is 0 or 1, and whereineach of L₁ and L₂ is independently selected from a substituted arylenegroup, a non-substituted arylene group, a substituted heteroarylenegroup or a non-substituted heteroarylene group, and b is 0 or
 1. 2. Theorganic compound according to claim 1, wherein each of R₁ and R₂ is oneof phenyl, alkylphenyl, biphenyl, alkylbiphenyl, halophenyl,alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl, naphthyl,alkylnaphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl,phenylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl,alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl, halopyrimidyl,cyanopyridimyl, alkoxypyrimidyl, phenylpyrimidyl, quinolinyl,isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl,naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl,arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl, imidazolyl,carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, phenylterpyridinyl,triphenylenyl, fluoranthenyl and diazafluorenyl.
 3. The organic compoundaccording to claim 1, wherein L₁ is one of phenylene, alkylphenylene,cyanophenylene, naphthylene, alkylnaphthylene, biphenylene,alkylbiphenylene, anthracenylene, pyrenylene, benzothiophenylene,benzofuranylene, dibenzothiophenylene, arylthiazolylene,dibenzofuranylene, fluorenylene and triphenylenylene, and wherein L₂ isone of phenylene and naphthylene.
 4. The organic compound according toclaim 1, wherein the organic compound is selected from:

.
 5. An organic light emitting diode, comprising: first and secondelectrodes facing each other; a first emitting part between the firstand second electrodes, and including a first emitting material layer andan electron transporting layer; a second emitting part between the firstemitting part and the second electrode, and including a second emittingmaterial layer; and a charge generation layer between the first andsecond emitting parts, wherein at least one of the electron transportinglayer and the charge generation layer includes an organic compoundrepresented by following Formula:

wherein each of X₁ and X₄ is a nitrogen atom, and each of X₂, X₃ and X₅is a carbon atom, wherein each of R₁ and R₂ is independently selectedfrom a substituted aryl group, a non-substituted aryl group, asubstituted heteroaryl group or a non-substituted heteroaryl group,wherein a is an integer between 0 to 3, and c is 0 or 1, and whereineach of L₁ and L₂ is independently selected from a substituted arylenegroup, a non-substituted arylene group, a substituted heteroarylenegroup or a non-substituted heteroarylene group, and b is 0 or
 1. 6. Theorganic light emitting diode according to claim 5, wherein each of R₁and R₂ is one of phenyl, alkylphenyl, biphenyl, alkylbiphenyl,halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl,naphthyl, alkylnaphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl,phenyinaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl,alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl, halopyrimidyl,cyanopyridimyl, alkoxypyrimidyl, phenylpyrimidyl, quinolinyl,isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl,naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl,arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl, imidazolyl,carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, phenylterpyridinyl,triphenylenyl, fluoranthenyl and diazafluorenyl.
 7. The organic lightemitting diode according to claim 5, wherein L₁ is one of phenylene,alkylphenylene, cyanophenylene, naphthylene, alkylnaphthylene,biphenylene, alkylbiphenylene, anthracenylene, pyrenylene,benzothiophenylene, benzofuranylene, dibenzothiophenylene,arylthiazolylene, dibenzofuranylene, fluorenylene and triphenylenylene,and wherein L₂ is one of phenylene and naphthylene.
 8. The organic lightemitting diode according to claim 5, wherein the organic compound isselected from:

.
 9. The organic light emitting diode according to claim 5, wherein oneof the first and second emitting material layers emits a blue light, andthe other one of the first and second emitting material layers emits ayellow-green light.
 10. The organic light emitting diode according toclaim 5, wherein the charge generation layer includes an N-type chargegeneration layer and a P-type charge generation layer, and the N-typecharge generation layer includes an alkali metal or an alkali earthmetal and the organic compound.
 11. The organic light emitting diodeaccording to claim 10, wherein the electron transporting layer isadjacent to the N-type charge generation layer.
 12. An organic lightemitting display device, comprising: a substrate; an organic lightemitting diode over the substrate and including: first and secondelectrodes facing each other, a first emitting part between the firstand second electrodes, and including a first emitting material layer andan electron transporting layer, a second emitting part between the firstemitting part, and the second electrode and including a second emittingmaterial layer, and a charge generation layer between the first andsecond emitting parts; and a thin film transistor between the substrateand the organic light emitting diode and connected to the firstelectrode, wherein at least one of the electron transporting layer andthe charge generation layer includes an organic compound represented byfollowing Formula:

wherein each of X₁ and X₄ is a nitrogen atom, and each of X₂, X₃ and X₅is a carbon atom, wherein each of R₁ and R₂ is independently selectedfrom a substituted aryl group, a non-substituted aryl group, asubstituted heteroaryl group or a non-substituted heteroaryl group,wherein a is an integer between 0 to 3, and c is 0 or 1, and whereineach of L₁ and L₂ is independently selected from a substituted arylenegroup, a non-substituted arylene group, a substituted heteroarylenegroup or a non-substituted heteroarylene group, and b is 0 or
 1. 13. Theorganic light emitting display device according to claim 12, whereineach of R₁ and R₂ is one of phonyl, alkylphenyl, biphenyl,alkylbiphenyl, halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl,silylphenyl, naphthyl, alkylnaphthyl, halonaphthyl, cyanonaphthyl,silylnaphthyl, phenylnaphthyl, pyridyl, alkylpyridyl, halopyridyl,cyanopyridyl, alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl,halopyrimidyl, cyanopyridirnyl, alkoxypyrimidyl, phenylpyrimidyl,quinolinyl, isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl,quinazolinyl, naphthyridinyl, benzothiophenyl, benzofuranyl,dibenzothiophenyl, arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl,imidazolyl, carbolinyl, phenanthrenyl, terphenyl, terpyridinyl,phenylterpyridinyl, triphenylenyl, fluoranthenyl and diazafluorenyl. 14.The organic light emitting display device according to claim 12, whereinL₁ is one of phenylene, alkylphenylene, cyanophenylene, naphthylene,alkylnaphthylene, biphenylene, alkylbiphenylene, anthracenylene,pyrenylene, benzothiophenylene, benzofuranylene, dibenzothiophenylene,arylthiazolylene, dibenzofuranylene, fluorenylene and triphenylenylene,and wherein L₂ is one of phenylene and naphthylene.
 15. The organiclight emitting display device according to claim 12, wherein the organiccompound is selected from:

.
 16. The organic light emitting display device according to claim 12,wherein one of the first and second emitting material layers emits ablue light, and the other one of the first and second emitting materiallayers emits a yellow-green light.
 17. The organic light emittingdisplay device according to claim 12, wherein the charge generationlayer includes an N-type charge generation layer and a P-type chargegeneration layer, and the N-type charge generation layer includes analkali metal or an alkali earth metal and the organic compound.
 18. Theorganic light emitting display device according to claim 17, wherein theelectron transporting layer is adjacent to the N-type charge generationlayer.